To link to the entire object, paste this link in email, IM or documentTo embed the entire object, paste this HTML in websiteTo link to this page, paste this link in email, IM or documentTo embed this page, paste this HTML in website

ANNUAL REPORT FOR 2005
Bethel Church Mitigation Site
Yadkin County
Project No. 6.779004T
TIP No. R-2120WM
Prepared By:
Natural Environment Unit & Roadside Environmental Unit
North Carolina Department of Transportation
December 2005
TABLE OF CONTENTS
SUMMARY.............................................................................................1
1.0 INTRODUCTION.............................................................................2
1.1 Project Description...............................................................................................2
1.2 Purpose .................................................................................................................2
1.3 Project History......................................................................................................4
2.0 HYDROLOGY..................................................................................5
2.1 Success Criteria ...................................................................................................5
2.2 Hydrologic Description ........................................................................................5
2.3 Results of Hydrologic Monitoring.......................................................................7
2.3.1 Site Data .........................................................................................................7
2.3.2 Climatic Data............................................................................................... 10
2.4 Conclusions........................................................................................................ 10
3.0 VEGETATION................................................................................12
3.1 Success Criteria ................................................................................................ 12
3.2 Description of Species ..................................................................................... 12
3.3 Results of Vegetation Monitoring.................................................................... 12
3.4 Conclusions........................................................................................................ 13
4.0 OVERALL CONCLUSIONS/ RECOMMENDATIONS .................13
FIGURES
Figure 1. Site Location Map............................................................................................ 3
Figure 2. Monitoring Gauge Location Map................................................................... 6
Figure 3. 2005 Hydrologic Monitoring Results. ........................................................... 9
Figure 4. 30-70 Percentile Graph................................................................................11
TABLES
Table 1. 2005 Hydrologic Monitoring Results...............................................................7
Table 2. Hydrologic Monitoring Results (2001-2005)..................................................8
Table 3. 2005 Vegetation Monitoring Results............................................................ 12
APPENDICES
APPENDIX A - GAUGE DATA GRAPHS
APPENDIX B - SITE PHOTOGRAPHS
1
SUMMARY
The following report summarizes the monitoring activities that have occurred in
the past year at the Bethel Church Mitigation Site. Site construction began in
December 2000 and was completed in February 2001. Monitoring activities in
2005 represent the fifth consecutive year of monitoring for the site. The site must
demonstrate both hydrologic and vegetation success for a minimum of five years
or until the site is deemed successful.
The site is monitored with six groundwater gauges (five in the restoration areas,
one in the existing wetland area), one rain gauge and four vegetation plots.
The daily rainfall data depicted on the monitoring gauge graphs was recorded
from an onsite rain gauge. An offsite rain gauge, maintained by the NC State
Climate Office in Yadkinville, contributed to the daily rainfall data and historical
rainfall data used for the 30th –70th percentile analysis.
The 2005-year represents the fifth consecutive year for hydrology monitoring.
Five of the six-groundwater gauges exceeded the optimum success criteria of
saturation within 12” of the soil surface for greater than 12.5% of the growing
season during an average rainfall year (two gauges met success for 100% of the
growing season). Gauge GW-2, which is located in the wetland enhancement
area, recorded hydrology for 10.8%, in spite of a data gap at the beginning of the
growing season. The groundwater gauges also revealed inundation in some
areas. Monitoring gauges 1, 2, 3 and 5 demonstrated groundwater level
fluctuations to specific rainfall events, and gauges 4 and 6 experienced periods
of ponding due to overbank flooding.
The 2005 vegetation monitoring of the site revealed an average density of 385
trees per acre, which is above the minimum success criteria of 260 trees per
acre. The stream channel was visually monitored during the annual vegetation
monitoring of the site. A bankfull event had been noted since the last monitoring
period. The channel was stable throughout the entire length.
Based on the hydrologic, vegetation, and streambank monitoring, the Bethel
Church Mitigation Site met the success criteria for the site during the 2005-
growing season. The site has demonstrated both hydrologic and vegetation
success for five consecutive years. NCDOT proposes to discontinue all
monitoring on the Bethel Church Mitigation Site.
2
1.0 INTRODUCTION
1.1 Project Description
The Bethel Church Mitigation Site is located on US 421, west of Yadkinville and
adjacent to an unnamed tributary to South Deep Creek in Yadkin County (Figure
1). This site mitigates for wetland impacts associated with the improvements to
US 421 New Location (R-2120AB).
The Bethel Church Mitigation Site is divided into two parcels (North and South),
totaling approximately 8.0 acres (ac) in size. The site consists of 3.03 acres of
bottomland hardwood wetland restoration, 0.8 acres of wetland enhancement,
850 feet of stream restoration and 4.2 acres of upland buffer. Site construction
began in December 2000 and was completed in February 2001. The site was
initially planted in March of 2001. In January 2002, supplemental planting was
performed in the enhancement area.
In addition to the original mitigation plan, the Department purchased Lots 1-20,
which are adjacent parcels of land to the west of Fox Drive and extending
(north) up to the Controlled Access along US 421. These parcels are completely
wooded, consisting of upland forest and bottomland hardwood floodplain
sections adjacent to the stream. By acquiring these parcels, the fill material
associated with Fox Drive was completely removed to match the wetland
mitigation site contours. The in-stream culvert was also removed during
construction.
1.2 Purpose
In order to demonstrate successful mitigation, hydrologic and vegetative
monitoring must be conducted for a minimum of five consecutive years. Success
criteria for hydrology and vegetation are based on the approved mitigation plan
dated August 1998. The following report details the results of hydrologic and
vegetative monitoring activities that were performed during the 2005-growing
season at the Bethel Church Mitigation Site.
3
Figure 1. Site Location Map
Yadkinville
4
1.3 Project History
August 1998 Mitigation Plan
February 2001 Site Construction Completed
March 2001 Site Planted
March 2001 Monitoring Gauges Installed
March- October 2001 Hydrologic Monitoring (1 yr.)
July 2001 Vegetation Monitoring (1 yr.)
January 2002 Enhancement Area Supplemental Planting
April- October 2002 Hydrologic Monitoring (2 yr.)
August 2002 Vegetation Monitori ng (2 yr.)
April-October 2003 Hydrologic Monitoring (3 yr.)
September 2003 Vegetation Monitoring (3 yr.)
April-October 2004 Hydrologic Monitoring (4 yr.)
June 2004 Vegetation Monitoring (4 yr.)
April-October 2005 Hydrologic Monitoring (5 yr.)
July 2005 Vegetation Monitoring (5 yr.)
5
2.0 HYDROLOGY
2.1 Success Criteria
Per the mitigation plan dated August 1998, surface and groundwater hydrology
on the Bethel Church Mitigation Site shall be monitored for five years following
the completion of all implementation activities, or until hydrologic success criteria
are met. Hydrologic success for this site is defined as the presence of the water
table within 12 inches of the soil surface for 5 -12 % of the growing season during
a normal rainfall year.
The growing season in Yadkin County begins April 9 and ends October 28.
These dates correspond to a 50% probability that temperatures will drop to 28°F
or lower after April 9 and before October 28.1 The growing season is 202 days;
therefore, optimum hydrology requires 12.5% of this season, or at least 25
consecutive days. Local climate must also represent average/normal conditions
for the area.
2.2 Hydrologic Description
In March 2001, six groundwater gauges were installed across the site (Figure 2).
The automatic monitoring gauges record daily readings of groundwater depth.
This represents the fifth growing season that the monitoring gauges have been in
place since construction of the site.
The Bethel Church Site was designed to restore the natural flooding regime of
the headwater stream. Hydrology for the site is naturally dominated by overbank
flooding of the small, unnamed tributary of South Deep Creek. The hydrologic
monitoring should show the reaction of the groundwater level to specific rainfall
events and the extent of ponding that may be attributed to overbank flooding.
1 Soil Conservation Service, Soil Survey of Yadkin County, North Carolina.
6
7
2.3 Results of Hydrologic Monitoring
2.3.1 Site Data
The maximum number of consecutive days that the groundwater was within
twelve inches of the surface was determined for each gauge. This number was
converted into a percentage of the 202-day growing season. The results are
presented in Table 1. Figure 3 also provides a graphical representation of the
hydrologic results. Gauges highlighted in blue indicate wetland hydrology for
more than 12.5% of the growing season. Gauges highlighted in green show
hydrology between 8% and 12.5% of the growing season. Those gauges
highlighted in red indicate wetland hydrology between 5% and 8%.
Appendix A contains a plot of the groundwater depth for each monitoring gauge.
The maximum number of consecutive days is noted on each graph. An onsite
rain gauge was used to obtain rainfall data from the site. It has been compared
with rainfall data obtained from the State Climate Office Local Weather Station in
Yadkinville, which is approximately 2 miles from the mitigation site.
Table 1. 2005 Hydrologic Monitoring Results
Monitoring
Gauge
<5% 5%-8% 8%-12.5% >12.5% Actual % Success Dates
GW-1* X 54.2
April 9-July 27
July 29-Sept 6
Sept. 17-Oct 28
GW-2 X 10.8
GW-3* X 13.8 May 18-June 14
GW-4* X 100 April 9-Oct 28
GW-5* X 67.0 June 15-Oct 28
GW-6* X 100 April 9-Oct 28
The highlighted gauge is located in the existing wetland enhancement area.
*Gauge met during an average rainfall month.
Specific Gauge Problems:
· Gauge (GW-2) experienced a malfunction (April 13-June 14). The gauge
was reading 6 times a day.
· Gauge (GW- 3) stopped recording data (April 23-May 17). The batteries
were replaced.
· Gauge (GW-5) stopped recording data (April 9-May 22). The batteries
were replaced.
8
Table 2. Hydrologic Monitoring Results (2001-2005)
Monitoring
Gauge
2001
Results
2002
Results
2003
Results
2004
Results
2005
Results
GW-1 11.4 15.8 48.3 100 54.2
GW-2 11.9 8.9 70.4 27.1 10.8
GW-3 11.4 24.1 100 100 13.8
GW-4 65.4 100 100 86.7 100
GW-5 34.7 9.9 100 100 67.0
GW-6 25.7 23.6 100 100 100
The highlighted gauge is located in the existing wetland enhancement area.
Table 2 represents hydrologic data in percentages from previous years (2001-
2005).
9
Figure 3. 2005 Hydrologic Monitoring Results
10
2.3.2 Climatic Data
Figure 4 is a comparison of monthly rainfall for the period of November 2004
through November 2005 to historical precipitation (collected between 1974 and
2005) for Yadkinville, North Carolina. This comparison gives an indication of how
2005 relates to historical data in terms of climate conditions. The NC State
Climate Office provided all local rainfall information.
For the 2005-year, November (’04), July, August, and November experienced
above average rainfall. The months of January, February, April, and September
recorded below average rainfall for the site, while December (’04), March, May,
June, and October recorded average rainfall. Overall, 2005 experienced an
average rainfall year.
2.4 Conclusions
The 2005-year represents the fifth consecutive year for hydrology monitoring.
Five of the six-groundwater gauges exceeded the optimum success criteria of
saturation within 12” of the soil surface for greater than 12.5% of the growing
season during an average rainfall year. Gauge GW-2, which is located in the
wetland enhancement area, recorded hydrology for 10.8% of the growing
season. The groundwater gauges also revealed inundation in some areas.
Monitoring gauges 1, 2, 3 and 5 demonstrated groundwater level fluctuations to
specific rainfall events, and gauges 4 and 6 experienced periods of ponding due
to overbank flooding.
This is the fifth consecutive year that the site hydrology has met the success
criteria; therefore, NCDOT proposes to discontinue hydrologic monitoring.
11
Figure 4: 30-70 Percentile Graph
Bethel Church 30-70 Percentile Graph
Yadkinville, NC
0
1
2
3
4
5
6
7
8
Nov 04' Dec 04' Jan 05' Feb 05' Mar 05' Apr 05' May 05' Jun 05' Jul 05' Aug 05' Sep 05' Oct 05' Nov 05'
Date
Precipitation (in)
2004 Rainfall 2005 Rainfall 30 Percentile 70 Percentile
70th Percentile
30th Percentile
12
3.0 VEGETATION: BETHEL CHURCH MITIGATION SITE
(YEAR 5 MONITORING)
3.1 Success Criteria
The success criteria are defined as 320 trees per acre of the target species
surviving at the end of three years and 260 trees per acre of the target species
surviving at the end of five years.
3.2 Description of Species
The following species were planted in the Wetland Restoration Area:
Carya cordiformis, Bitternut Hickory
Fraxinus pennsylvanica, Green Ash
Platanus occidentalis, Sycamore
Quercus nigra, Water Oak
Quercus palustris, Pin Oak
Quercus phellos, Willow Oak
Quercus rubra, Northern Red Oak
3.3 Results of Vegetation Monitoring
Table 3. 2005 Vegetation Monitoring Results
Plot #
Bitternut Hickory
Green Ash
Sycamore
Water Oak
Pin Oak
Willow Oak
Northern Red Oak
Total (5 year)
Total (at planting)
Density (Trees/Acre)
1 4 10 3 6 1 24 36 453
2 15 4 4 23 40 391
3 15 2 1 8 26 51 347
4 14 1 1 7 23 45 348
AVERAGE DENSITY 385
13
Site Notes: Other species noted: foxtail, ragweed, red maple, Juncus sp.,
Panicum sp., Sagittaria sp., smartweed, cattail, woolgrass, briars, fennel,
pokeweed, silky dogwood, black willow, multi-flora rose, poison ivy, volunteer
green ash, lespedeza, goldenrod, river birch, tulip poplar, and tag alder. Plot 2
had heavy growth competition, which made it difficult to find trees. Northern Red
Oak was noted growing in higher elevations on the site.
3.4 Conclusions
Red maples in the enhancement area (area around plot 2) were cut and treated
with Oust in December 2001. This treatment has been successful in suppressing
the red maples. Trees were supplementally planted in the area around plots one
and two in January 2002. The 2005 vegetation monitoring of the site revealed an
average density of 385 trees per acre, which is above the minimum success
criteria of 260 trees per acre.
The stream channel was visually inspected during the annual vegetation
monitoring of the site. A bankfull event had been noted since the last monitoring
period. The streambanks were highly vegetated with herbaceous species, black
willow, silky dogwood, and tag alder. The channel was stable throughout the
entire length. Photos 9 through 14 show the conditions of the stream. No
maintenance actions are necessary.
NCDOT proposes to discontinue vegetation and channel stability monitoring at
the Bethel Church Mitigation Site
4.0 OVERALL CONCLUSIONS/ RECOMMENDATIONS
The Bethel Church Mitigation Site has met the success criteria prescribed in the
mitigation plan during an average rainfall year. Five of the six-groundwater
gauges exceeded the optimum success criteria of saturation within 12” of the soil
surface for greater than 12.5% of the growing season during an average rainfall
year. Gauge GW-2, which is located in the wetland enhancement area, recorded
hydrology for 10.8%, in spite of a data gap (instrument stopped recording) at the
beginning of the growing season. The groundwater gauges also revealed
inundation in some areas.
The site demonstrated an average density of 385 trees per acre, which is above
the minimum success criteria of 260 trees per acre. The stream channel was
visually inspected during the annual vegetation monitoring of the site. A bankfull
event had been noted since the last monitoring period. The channel was stable
throughout the entire length.
Based on the hydrologic, vegetation, and streambank monitoring, the Bethel
Church Mitigation Site met the success criteria for the site during the 2005-
growing season. The site has demonstrated both hydrologic and vegetation
success for five consecutive years. NCDOT proposes to discontinue all
monitoring on the Bethel Church Mitigation Site.
14
APPENDIX A
GAUGE DATA GRAPHS
15
APPENDIX B
SITE PHOTOGRAPHS
PHOTO LOCATIONS & MONITORING PLOTS
16
Bethel Church
Photo 1 Photo 2
Photo 3 Photo 4
Photo 5 Photo 6
August 2005
17
Photo 7 Photo 8
Photo 9 (Stream) Photo 10 (Stream)
Photo 11 (Stream) Photo 12 (Stream)
August 2005
18
Photo 13 (Stream) Photo 14 (Stream)
August 2005
19
GROUNDWATER GAUGES
Bethel Church BC-G1
-30
-25
-20
-15
-10
-5
0
5
10
01-Jan-05
11-Jan-05
21-Jan-05
31-Jan-05
10-Feb-05
20-Feb-05
02-Mar-05
12-Mar-05
22-Mar-05
01-Apr-05
11-Apr-05
21-Apr-05
01-May-05
11-May-05
21-May-05
31-May-05
10-Jun-05
20-Jun-05
30-Jun-05
10-Jul-05
20-Jul-05
30-Jul-05
09-Aug-05
19-Aug-05
29-Aug-05
08-Sep-05
18-Sep-05
28-Sep-05
08-Oct-05
18-Oct-05
28-Oct-05
Date
Depth to Groundwater (in)
0
0.5
1
1.5
2
2.5
3
3.5
4
Precipitation (in)
RG7 BC-G1 REQUIRED DEPTH
Beginning of
growing season
End of
growing
season
Replaced gauge
110 Days
40 Days
42 Days
Bethel Church BC-G2
-30
-25
-20
-15
-10
-5
0
5
10
01-Jan-05
11-Jan-05
21-Jan-05
31-Jan-05
10-Feb-05
20-Feb-05
02-Mar-05
12-Mar-05
22-Mar-05
01-Apr-05
11-Apr-05
21-Apr-05
01-May-05
11-May-05
21-May-05
31-May-05
10-Jun-05
20-Jun-05
30-Jun-05
10-Jul-05
20-Jul-05
30-Jul-05
09-Aug-05
19-Aug-05
29-Aug-05
08-Sep-05
18-Sep-05
28-Sep-05
08-Oct-05
18-Oct-05
28-Oct-05
Date
Depth to Groundwater (in)
0
0.5
1
1.5
2
2.5
3
3.5
4
(existing wetland enhancement area)
Precipitation (in)
RG7 BC-G2 REQUIRED DEPTH
Beginning of
growing season
End of
growing
season
Gauge Malfunction
22 Days
Bethel Church BC-G3
-30
-25
-20
-15
-10
-5
0
5
10
01-Jan-05
11-Jan-05
21-Jan-05
31-Jan-05
10-Feb-05
20-Feb-05
02-Mar-05
12-Mar-05
22-Mar-05
01-Apr-05
11-Apr-05
21-Apr-05
01-May-05
11-May-05
21-May-05
31-May-05
10-Jun-05
20-Jun-05
30-Jun-05
10-Jul-05
20-Jul-05
30-Jul-05
09-Aug-05
19-Aug-05
29-Aug-05
08-Sep-05
18-Sep-05
28-Sep-05
08-Oct-05
18-Oct-05
28-Oct-05
Date
Depth to Groundwater (in)
0
0.5
1
1.5
2
2.5
3
3.5
4
Precipitation (in)
RG7 BC-G3 REQUIRED DEPTH
Beginning of
growing season
End of
growing
season
Data contains gaps
in reading
Gauge
Malfunction
Gauge
malfunction
22 Days
28 Days
Bethel Church BC-G4
-30
-25
-20
-15
-10
-5
0
5
10
01-Jan-05
11-Jan-05
21-Jan-05
31-Jan-05
10-Feb-05
20-Feb-05
02-Mar-05
12-Mar-05
22-Mar-05
01-Apr-05
11-Apr-05
21-Apr-05
01-May-05
11-May-05
21-May-05
31-May-05
10-Jun-05
20-Jun-05
30-Jun-05
10-Jul-05
20-Jul-05
30-Jul-05
09-Aug-05
19-Aug-05
29-Aug-05
08-Sep-05
18-Sep-05
28-Sep-05
08-Oct-05
18-Oct-05
28-Oct-05
Date
Depth to Groundwater (in)
0
0.5
1
1.5
2
2.5
3
3.5
4
Precipitation (in)
RG7 BC-G4 REQUIRED DEPTH
Beginning of
growing season
End of
growing
season
Standing water
observed
203 Days
Bethel Church BC-G5
-30
-25
-20
-15
-10
-5
0
5
10
01-Jan-05
11-Jan-05
21-Jan-05
31-Jan-05
10-Feb-05
20-Feb-05
02-Mar-05
12-Mar-05
22-Mar-05
01-Apr-05
11-Apr-05
21-Apr-05
01-May-05
11-May-05
21-May-05
31-May-05
10-Jun-05
20-Jun-05
30-Jun-05
10-Jul-05
20-Jul-05
30-Jul-05
09-Aug-05
19-Aug-05
29-Aug-05
08-Sep-05
18-Sep-05
28-Sep-05
08-Oct-05
18-Oct-05
28-Oct-05
Date
Depth to Groundwater (in)
0
0.5
1
1.5
2
2.5
3
3.5
4
Precipitation (in)
RG7 BC-G5 REQUIRED DEPTH
Beginning of
growing season
End of
growing
season
Gauge
Malfunction
Replaced
gauge
21 Days
136 Days
Bethel Church BC-G6
-30
-25
-20
-15
-10
-5
0
5
10
01-Jan-05
11-Jan-05
21-Jan-05
31-Jan-05
10-Feb-05
20-Feb-05
02-Mar-05
12-Mar-05
22-Mar-05
01-Apr-05
11-Apr-05
21-Apr-05
01-May-05
11-May-05
21-May-05
31-May-05
10-Jun-05
20-Jun-05
30-Jun-05
10-Jul-05
20-Jul-05
30-Jul-05
09-Aug-05
19-Aug-05
29-Aug-05
08-Sep-05
18-Sep-05
28-Sep-05
08-Oct-05
18-Oct-05
28-Oct-05
Date
Depth to Groundwater (in)
0
0.5
1
1.5
2
2.5
3
3.5
4
Precipitation (in)
RG7 BC-G6 REQUIRED DEPTH
Beginning of
growing
season
End of
growing
season
Standing water
observed
Replaced
gauge
203 Days

ANNUAL REPORT FOR 2005
Bethel Church Mitigation Site
Yadkin County
Project No. 6.779004T
TIP No. R-2120WM
Prepared By:
Natural Environment Unit & Roadside Environmental Unit
North Carolina Department of Transportation
December 2005
TABLE OF CONTENTS
SUMMARY.............................................................................................1
1.0 INTRODUCTION.............................................................................2
1.1 Project Description...............................................................................................2
1.2 Purpose .................................................................................................................2
1.3 Project History......................................................................................................4
2.0 HYDROLOGY..................................................................................5
2.1 Success Criteria ...................................................................................................5
2.2 Hydrologic Description ........................................................................................5
2.3 Results of Hydrologic Monitoring.......................................................................7
2.3.1 Site Data .........................................................................................................7
2.3.2 Climatic Data............................................................................................... 10
2.4 Conclusions........................................................................................................ 10
3.0 VEGETATION................................................................................12
3.1 Success Criteria ................................................................................................ 12
3.2 Description of Species ..................................................................................... 12
3.3 Results of Vegetation Monitoring.................................................................... 12
3.4 Conclusions........................................................................................................ 13
4.0 OVERALL CONCLUSIONS/ RECOMMENDATIONS .................13
FIGURES
Figure 1. Site Location Map............................................................................................ 3
Figure 2. Monitoring Gauge Location Map................................................................... 6
Figure 3. 2005 Hydrologic Monitoring Results. ........................................................... 9
Figure 4. 30-70 Percentile Graph................................................................................11
TABLES
Table 1. 2005 Hydrologic Monitoring Results...............................................................7
Table 2. Hydrologic Monitoring Results (2001-2005)..................................................8
Table 3. 2005 Vegetation Monitoring Results............................................................ 12
APPENDICES
APPENDIX A - GAUGE DATA GRAPHS
APPENDIX B - SITE PHOTOGRAPHS
1
SUMMARY
The following report summarizes the monitoring activities that have occurred in
the past year at the Bethel Church Mitigation Site. Site construction began in
December 2000 and was completed in February 2001. Monitoring activities in
2005 represent the fifth consecutive year of monitoring for the site. The site must
demonstrate both hydrologic and vegetation success for a minimum of five years
or until the site is deemed successful.
The site is monitored with six groundwater gauges (five in the restoration areas,
one in the existing wetland area), one rain gauge and four vegetation plots.
The daily rainfall data depicted on the monitoring gauge graphs was recorded
from an onsite rain gauge. An offsite rain gauge, maintained by the NC State
Climate Office in Yadkinville, contributed to the daily rainfall data and historical
rainfall data used for the 30th –70th percentile analysis.
The 2005-year represents the fifth consecutive year for hydrology monitoring.
Five of the six-groundwater gauges exceeded the optimum success criteria of
saturation within 12” of the soil surface for greater than 12.5% of the growing
season during an average rainfall year (two gauges met success for 100% of the
growing season). Gauge GW-2, which is located in the wetland enhancement
area, recorded hydrology for 10.8%, in spite of a data gap at the beginning of the
growing season. The groundwater gauges also revealed inundation in some
areas. Monitoring gauges 1, 2, 3 and 5 demonstrated groundwater level
fluctuations to specific rainfall events, and gauges 4 and 6 experienced periods
of ponding due to overbank flooding.
The 2005 vegetation monitoring of the site revealed an average density of 385
trees per acre, which is above the minimum success criteria of 260 trees per
acre. The stream channel was visually monitored during the annual vegetation
monitoring of the site. A bankfull event had been noted since the last monitoring
period. The channel was stable throughout the entire length.
Based on the hydrologic, vegetation, and streambank monitoring, the Bethel
Church Mitigation Site met the success criteria for the site during the 2005-
growing season. The site has demonstrated both hydrologic and vegetation
success for five consecutive years. NCDOT proposes to discontinue all
monitoring on the Bethel Church Mitigation Site.
2
1.0 INTRODUCTION
1.1 Project Description
The Bethel Church Mitigation Site is located on US 421, west of Yadkinville and
adjacent to an unnamed tributary to South Deep Creek in Yadkin County (Figure
1). This site mitigates for wetland impacts associated with the improvements to
US 421 New Location (R-2120AB).
The Bethel Church Mitigation Site is divided into two parcels (North and South),
totaling approximately 8.0 acres (ac) in size. The site consists of 3.03 acres of
bottomland hardwood wetland restoration, 0.8 acres of wetland enhancement,
850 feet of stream restoration and 4.2 acres of upland buffer. Site construction
began in December 2000 and was completed in February 2001. The site was
initially planted in March of 2001. In January 2002, supplemental planting was
performed in the enhancement area.
In addition to the original mitigation plan, the Department purchased Lots 1-20,
which are adjacent parcels of land to the west of Fox Drive and extending
(north) up to the Controlled Access along US 421. These parcels are completely
wooded, consisting of upland forest and bottomland hardwood floodplain
sections adjacent to the stream. By acquiring these parcels, the fill material
associated with Fox Drive was completely removed to match the wetland
mitigation site contours. The in-stream culvert was also removed during
construction.
1.2 Purpose
In order to demonstrate successful mitigation, hydrologic and vegetative
monitoring must be conducted for a minimum of five consecutive years. Success
criteria for hydrology and vegetation are based on the approved mitigation plan
dated August 1998. The following report details the results of hydrologic and
vegetative monitoring activities that were performed during the 2005-growing
season at the Bethel Church Mitigation Site.
3
Figure 1. Site Location Map
Yadkinville
4
1.3 Project History
August 1998 Mitigation Plan
February 2001 Site Construction Completed
March 2001 Site Planted
March 2001 Monitoring Gauges Installed
March- October 2001 Hydrologic Monitoring (1 yr.)
July 2001 Vegetation Monitoring (1 yr.)
January 2002 Enhancement Area Supplemental Planting
April- October 2002 Hydrologic Monitoring (2 yr.)
August 2002 Vegetation Monitori ng (2 yr.)
April-October 2003 Hydrologic Monitoring (3 yr.)
September 2003 Vegetation Monitoring (3 yr.)
April-October 2004 Hydrologic Monitoring (4 yr.)
June 2004 Vegetation Monitoring (4 yr.)
April-October 2005 Hydrologic Monitoring (5 yr.)
July 2005 Vegetation Monitoring (5 yr.)
5
2.0 HYDROLOGY
2.1 Success Criteria
Per the mitigation plan dated August 1998, surface and groundwater hydrology
on the Bethel Church Mitigation Site shall be monitored for five years following
the completion of all implementation activities, or until hydrologic success criteria
are met. Hydrologic success for this site is defined as the presence of the water
table within 12 inches of the soil surface for 5 -12 % of the growing season during
a normal rainfall year.
The growing season in Yadkin County begins April 9 and ends October 28.
These dates correspond to a 50% probability that temperatures will drop to 28°F
or lower after April 9 and before October 28.1 The growing season is 202 days;
therefore, optimum hydrology requires 12.5% of this season, or at least 25
consecutive days. Local climate must also represent average/normal conditions
for the area.
2.2 Hydrologic Description
In March 2001, six groundwater gauges were installed across the site (Figure 2).
The automatic monitoring gauges record daily readings of groundwater depth.
This represents the fifth growing season that the monitoring gauges have been in
place since construction of the site.
The Bethel Church Site was designed to restore the natural flooding regime of
the headwater stream. Hydrology for the site is naturally dominated by overbank
flooding of the small, unnamed tributary of South Deep Creek. The hydrologic
monitoring should show the reaction of the groundwater level to specific rainfall
events and the extent of ponding that may be attributed to overbank flooding.
1 Soil Conservation Service, Soil Survey of Yadkin County, North Carolina.
6
7
2.3 Results of Hydrologic Monitoring
2.3.1 Site Data
The maximum number of consecutive days that the groundwater was within
twelve inches of the surface was determined for each gauge. This number was
converted into a percentage of the 202-day growing season. The results are
presented in Table 1. Figure 3 also provides a graphical representation of the
hydrologic results. Gauges highlighted in blue indicate wetland hydrology for
more than 12.5% of the growing season. Gauges highlighted in green show
hydrology between 8% and 12.5% of the growing season. Those gauges
highlighted in red indicate wetland hydrology between 5% and 8%.
Appendix A contains a plot of the groundwater depth for each monitoring gauge.
The maximum number of consecutive days is noted on each graph. An onsite
rain gauge was used to obtain rainfall data from the site. It has been compared
with rainfall data obtained from the State Climate Office Local Weather Station in
Yadkinville, which is approximately 2 miles from the mitigation site.
Table 1. 2005 Hydrologic Monitoring Results
Monitoring
Gauge
<5% 5%-8% 8%-12.5% >12.5% Actual % Success Dates
GW-1* X 54.2
April 9-July 27
July 29-Sept 6
Sept. 17-Oct 28
GW-2 X 10.8
GW-3* X 13.8 May 18-June 14
GW-4* X 100 April 9-Oct 28
GW-5* X 67.0 June 15-Oct 28
GW-6* X 100 April 9-Oct 28
The highlighted gauge is located in the existing wetland enhancement area.
*Gauge met during an average rainfall month.
Specific Gauge Problems:
· Gauge (GW-2) experienced a malfunction (April 13-June 14). The gauge
was reading 6 times a day.
· Gauge (GW- 3) stopped recording data (April 23-May 17). The batteries
were replaced.
· Gauge (GW-5) stopped recording data (April 9-May 22). The batteries
were replaced.
8
Table 2. Hydrologic Monitoring Results (2001-2005)
Monitoring
Gauge
2001
Results
2002
Results
2003
Results
2004
Results
2005
Results
GW-1 11.4 15.8 48.3 100 54.2
GW-2 11.9 8.9 70.4 27.1 10.8
GW-3 11.4 24.1 100 100 13.8
GW-4 65.4 100 100 86.7 100
GW-5 34.7 9.9 100 100 67.0
GW-6 25.7 23.6 100 100 100
The highlighted gauge is located in the existing wetland enhancement area.
Table 2 represents hydrologic data in percentages from previous years (2001-
2005).
9
Figure 3. 2005 Hydrologic Monitoring Results
10
2.3.2 Climatic Data
Figure 4 is a comparison of monthly rainfall for the period of November 2004
through November 2005 to historical precipitation (collected between 1974 and
2005) for Yadkinville, North Carolina. This comparison gives an indication of how
2005 relates to historical data in terms of climate conditions. The NC State
Climate Office provided all local rainfall information.
For the 2005-year, November (’04), July, August, and November experienced
above average rainfall. The months of January, February, April, and September
recorded below average rainfall for the site, while December (’04), March, May,
June, and October recorded average rainfall. Overall, 2005 experienced an
average rainfall year.
2.4 Conclusions
The 2005-year represents the fifth consecutive year for hydrology monitoring.
Five of the six-groundwater gauges exceeded the optimum success criteria of
saturation within 12” of the soil surface for greater than 12.5% of the growing
season during an average rainfall year. Gauge GW-2, which is located in the
wetland enhancement area, recorded hydrology for 10.8% of the growing
season. The groundwater gauges also revealed inundation in some areas.
Monitoring gauges 1, 2, 3 and 5 demonstrated groundwater level fluctuations to
specific rainfall events, and gauges 4 and 6 experienced periods of ponding due
to overbank flooding.
This is the fifth consecutive year that the site hydrology has met the success
criteria; therefore, NCDOT proposes to discontinue hydrologic monitoring.
11
Figure 4: 30-70 Percentile Graph
Bethel Church 30-70 Percentile Graph
Yadkinville, NC
0
1
2
3
4
5
6
7
8
Nov 04' Dec 04' Jan 05' Feb 05' Mar 05' Apr 05' May 05' Jun 05' Jul 05' Aug 05' Sep 05' Oct 05' Nov 05'
Date
Precipitation (in)
2004 Rainfall 2005 Rainfall 30 Percentile 70 Percentile
70th Percentile
30th Percentile
12
3.0 VEGETATION: BETHEL CHURCH MITIGATION SITE
(YEAR 5 MONITORING)
3.1 Success Criteria
The success criteria are defined as 320 trees per acre of the target species
surviving at the end of three years and 260 trees per acre of the target species
surviving at the end of five years.
3.2 Description of Species
The following species were planted in the Wetland Restoration Area:
Carya cordiformis, Bitternut Hickory
Fraxinus pennsylvanica, Green Ash
Platanus occidentalis, Sycamore
Quercus nigra, Water Oak
Quercus palustris, Pin Oak
Quercus phellos, Willow Oak
Quercus rubra, Northern Red Oak
3.3 Results of Vegetation Monitoring
Table 3. 2005 Vegetation Monitoring Results
Plot #
Bitternut Hickory
Green Ash
Sycamore
Water Oak
Pin Oak
Willow Oak
Northern Red Oak
Total (5 year)
Total (at planting)
Density (Trees/Acre)
1 4 10 3 6 1 24 36 453
2 15 4 4 23 40 391
3 15 2 1 8 26 51 347
4 14 1 1 7 23 45 348
AVERAGE DENSITY 385
13
Site Notes: Other species noted: foxtail, ragweed, red maple, Juncus sp.,
Panicum sp., Sagittaria sp., smartweed, cattail, woolgrass, briars, fennel,
pokeweed, silky dogwood, black willow, multi-flora rose, poison ivy, volunteer
green ash, lespedeza, goldenrod, river birch, tulip poplar, and tag alder. Plot 2
had heavy growth competition, which made it difficult to find trees. Northern Red
Oak was noted growing in higher elevations on the site.
3.4 Conclusions
Red maples in the enhancement area (area around plot 2) were cut and treated
with Oust in December 2001. This treatment has been successful in suppressing
the red maples. Trees were supplementally planted in the area around plots one
and two in January 2002. The 2005 vegetation monitoring of the site revealed an
average density of 385 trees per acre, which is above the minimum success
criteria of 260 trees per acre.
The stream channel was visually inspected during the annual vegetation
monitoring of the site. A bankfull event had been noted since the last monitoring
period. The streambanks were highly vegetated with herbaceous species, black
willow, silky dogwood, and tag alder. The channel was stable throughout the
entire length. Photos 9 through 14 show the conditions of the stream. No
maintenance actions are necessary.
NCDOT proposes to discontinue vegetation and channel stability monitoring at
the Bethel Church Mitigation Site
4.0 OVERALL CONCLUSIONS/ RECOMMENDATIONS
The Bethel Church Mitigation Site has met the success criteria prescribed in the
mitigation plan during an average rainfall year. Five of the six-groundwater
gauges exceeded the optimum success criteria of saturation within 12” of the soil
surface for greater than 12.5% of the growing season during an average rainfall
year. Gauge GW-2, which is located in the wetland enhancement area, recorded
hydrology for 10.8%, in spite of a data gap (instrument stopped recording) at the
beginning of the growing season. The groundwater gauges also revealed
inundation in some areas.
The site demonstrated an average density of 385 trees per acre, which is above
the minimum success criteria of 260 trees per acre. The stream channel was
visually inspected during the annual vegetation monitoring of the site. A bankfull
event had been noted since the last monitoring period. The channel was stable
throughout the entire length.
Based on the hydrologic, vegetation, and streambank monitoring, the Bethel
Church Mitigation Site met the success criteria for the site during the 2005-
growing season. The site has demonstrated both hydrologic and vegetation
success for five consecutive years. NCDOT proposes to discontinue all
monitoring on the Bethel Church Mitigation Site.
14
APPENDIX A
GAUGE DATA GRAPHS
15
APPENDIX B
SITE PHOTOGRAPHS
PHOTO LOCATIONS & MONITORING PLOTS
16
Bethel Church
Photo 1 Photo 2
Photo 3 Photo 4
Photo 5 Photo 6
August 2005
17
Photo 7 Photo 8
Photo 9 (Stream) Photo 10 (Stream)
Photo 11 (Stream) Photo 12 (Stream)
August 2005
18
Photo 13 (Stream) Photo 14 (Stream)
August 2005
19
GROUNDWATER GAUGES
Bethel Church BC-G1
-30
-25
-20
-15
-10
-5
0
5
10
01-Jan-05
11-Jan-05
21-Jan-05
31-Jan-05
10-Feb-05
20-Feb-05
02-Mar-05
12-Mar-05
22-Mar-05
01-Apr-05
11-Apr-05
21-Apr-05
01-May-05
11-May-05
21-May-05
31-May-05
10-Jun-05
20-Jun-05
30-Jun-05
10-Jul-05
20-Jul-05
30-Jul-05
09-Aug-05
19-Aug-05
29-Aug-05
08-Sep-05
18-Sep-05
28-Sep-05
08-Oct-05
18-Oct-05
28-Oct-05
Date
Depth to Groundwater (in)
0
0.5
1
1.5
2
2.5
3
3.5
4
Precipitation (in)
RG7 BC-G1 REQUIRED DEPTH
Beginning of
growing season
End of
growing
season
Replaced gauge
110 Days
40 Days
42 Days
Bethel Church BC-G2
-30
-25
-20
-15
-10
-5
0
5
10
01-Jan-05
11-Jan-05
21-Jan-05
31-Jan-05
10-Feb-05
20-Feb-05
02-Mar-05
12-Mar-05
22-Mar-05
01-Apr-05
11-Apr-05
21-Apr-05
01-May-05
11-May-05
21-May-05
31-May-05
10-Jun-05
20-Jun-05
30-Jun-05
10-Jul-05
20-Jul-05
30-Jul-05
09-Aug-05
19-Aug-05
29-Aug-05
08-Sep-05
18-Sep-05
28-Sep-05
08-Oct-05
18-Oct-05
28-Oct-05
Date
Depth to Groundwater (in)
0
0.5
1
1.5
2
2.5
3
3.5
4
(existing wetland enhancement area)
Precipitation (in)
RG7 BC-G2 REQUIRED DEPTH
Beginning of
growing season
End of
growing
season
Gauge Malfunction
22 Days
Bethel Church BC-G3
-30
-25
-20
-15
-10
-5
0
5
10
01-Jan-05
11-Jan-05
21-Jan-05
31-Jan-05
10-Feb-05
20-Feb-05
02-Mar-05
12-Mar-05
22-Mar-05
01-Apr-05
11-Apr-05
21-Apr-05
01-May-05
11-May-05
21-May-05
31-May-05
10-Jun-05
20-Jun-05
30-Jun-05
10-Jul-05
20-Jul-05
30-Jul-05
09-Aug-05
19-Aug-05
29-Aug-05
08-Sep-05
18-Sep-05
28-Sep-05
08-Oct-05
18-Oct-05
28-Oct-05
Date
Depth to Groundwater (in)
0
0.5
1
1.5
2
2.5
3
3.5
4
Precipitation (in)
RG7 BC-G3 REQUIRED DEPTH
Beginning of
growing season
End of
growing
season
Data contains gaps
in reading
Gauge
Malfunction
Gauge
malfunction
22 Days
28 Days
Bethel Church BC-G4
-30
-25
-20
-15
-10
-5
0
5
10
01-Jan-05
11-Jan-05
21-Jan-05
31-Jan-05
10-Feb-05
20-Feb-05
02-Mar-05
12-Mar-05
22-Mar-05
01-Apr-05
11-Apr-05
21-Apr-05
01-May-05
11-May-05
21-May-05
31-May-05
10-Jun-05
20-Jun-05
30-Jun-05
10-Jul-05
20-Jul-05
30-Jul-05
09-Aug-05
19-Aug-05
29-Aug-05
08-Sep-05
18-Sep-05
28-Sep-05
08-Oct-05
18-Oct-05
28-Oct-05
Date
Depth to Groundwater (in)
0
0.5
1
1.5
2
2.5
3
3.5
4
Precipitation (in)
RG7 BC-G4 REQUIRED DEPTH
Beginning of
growing season
End of
growing
season
Standing water
observed
203 Days
Bethel Church BC-G5
-30
-25
-20
-15
-10
-5
0
5
10
01-Jan-05
11-Jan-05
21-Jan-05
31-Jan-05
10-Feb-05
20-Feb-05
02-Mar-05
12-Mar-05
22-Mar-05
01-Apr-05
11-Apr-05
21-Apr-05
01-May-05
11-May-05
21-May-05
31-May-05
10-Jun-05
20-Jun-05
30-Jun-05
10-Jul-05
20-Jul-05
30-Jul-05
09-Aug-05
19-Aug-05
29-Aug-05
08-Sep-05
18-Sep-05
28-Sep-05
08-Oct-05
18-Oct-05
28-Oct-05
Date
Depth to Groundwater (in)
0
0.5
1
1.5
2
2.5
3
3.5
4
Precipitation (in)
RG7 BC-G5 REQUIRED DEPTH
Beginning of
growing season
End of
growing
season
Gauge
Malfunction
Replaced
gauge
21 Days
136 Days
Bethel Church BC-G6
-30
-25
-20
-15
-10
-5
0
5
10
01-Jan-05
11-Jan-05
21-Jan-05
31-Jan-05
10-Feb-05
20-Feb-05
02-Mar-05
12-Mar-05
22-Mar-05
01-Apr-05
11-Apr-05
21-Apr-05
01-May-05
11-May-05
21-May-05
31-May-05
10-Jun-05
20-Jun-05
30-Jun-05
10-Jul-05
20-Jul-05
30-Jul-05
09-Aug-05
19-Aug-05
29-Aug-05
08-Sep-05
18-Sep-05
28-Sep-05
08-Oct-05
18-Oct-05
28-Oct-05
Date
Depth to Groundwater (in)
0
0.5
1
1.5
2
2.5
3
3.5
4
Precipitation (in)
RG7 BC-G6 REQUIRED DEPTH
Beginning of
growing
season
End of
growing
season
Standing water
observed
Replaced
gauge
203 Days